Residential and commercial air conditioners include as a part thereof a fan coil unit located within a housing which includes a coil through which refrigerant (liquid or gas, such as Freon) is pumped. The coil is normally supported above a condensation pan, convector tray or primary pan having one or more openings through which air is blown by one or more fans powered by motors which are supported below and from the primary pan. The air passing through the coil creates condensation on the coil which drips down, upon and into the primary pan and is then conducted by an appropriate outlet through a discharge pipe into a secondary pan and/or an associated drain.
Such conventional primary pans are generally made from galvanized metal and rust with relative ease. The fasteners (nuts and bolts and/or rivets) which connect the fan and/or fan housings to the primary pan are also generally made from metal and rust with equal relative ease. Once the primary pan and/or the fasteners rust, the condensation/water normally accumulating therein and draining properly therefrom, cannot do so. Instead the condensation/condensate can, for example, drip through the rusted galvanized primary pan and/or the fasteners into the underlying motor(s) which drives the fan(s) thereby causing the motor to short-out. The fan motor itself is normally supported by a metallic bracket and excessive rusting of the primary pans/metal fasteners will cause the fan support brackets to rust. Excessive rusting coupled with the centrifugal force of the fan motor would cause wobble, undesirable increased noise, and could eventually result in the brackets breaking or sufficiently loosening such that the motors and pans simply fall from the primary pan.
Excessive rust also blocks or reduces normal drainage which results in condensate accumulating in the primary pan to such an extent that the same overflows and causes damage. For example, conventional fan coil units are normally mounted on floors or in ceilings in hotels, motels and the like. Obviously, if a primary pan outlet becomes blocked and the condensate overflows, it will damage the ceiling and/or walls or the underlying floor and associated rugs. Accordingly, concern is not simply limited to fan coil unit damage, but extends to structural damage of the commercial or residential structure.
U.S. Pat. No. 4,856,672 and U.S. Pat. No. 4,986,087 each disclose structure which reduces rust and fungus growth associated with conventional galvanized metal primary pans and their associated sponge rubber seals o rubber gaskets which deteriorate and virtually break-down into "dust" or similar extremely small particles which block or reduce the drainage of condensate from the pans and also results in fungus growth which in turn causes undesirable odors. The latter patents overcome these disadvantages by constructing the primary pans from synthetic polymeric material and utilizing a baffle to close a gap between the bottom of the condensation coil and the primary pan. Since the air which normally passes through this gap can now not pass therethrough due to the baffle, the efficiency of the overall unit is appreciably increases and the absence of metal, sponge rubber seals and rubber gaskets prevents deterioration which in turn reduces/eliminates the aforementioned damage.
The latter patents also avoid the fungus/odor problem by admixing biocides or preservative additives with the polymeric material from which the primary pans are formed. The latter reduces mildew, odors, etc.